7. A solution has formic acid at 5 mM, and formic ion at 6 mM, to which 5 mM HCl is added. What is the pH of this solution? (pKa of formic acid is 3.7) (10%)

2. If we consider a 850 MHz NMR spectrometer, the resonance of 1H nuclear is 850MHz. calculate the energy that is required to make the transition from the lower energy state to the higher state. Meanwhile, please explain how to calculate the population ratio of molecules in the higher and lower states? (8%)